Suppose a consumer has the utility function u(Z1, Z2) = Z1 + Z2,
1. In a labelled diagram, illustrate the indifference curve which yields a utility level of 3.5.
2. If the consumer has income M and faces the prices p1 and p2 for z1 and z2, respectively, find demand functions for the two goods.
3. What types of preferences are associated with such a utility function?